BR excess temperature

What does A793 mean?

The brake resistor temperature has exceeded the warning limit defined by parameter 43.12. This indicates the resistor is overheating, potentially due to excessive braking duty or improper dimensioning. Continued operation risks damage to the resistor or associated components.

• Excessive braking duty cycle or duration (e.g., rapid decelerations, heavy regenerative loads) exceeding the brake resistor's thermal capacity.
• Brake resistor is undersized for the application (e.g., actual power dissipation exceeds `P43.09` (Brake resistor power)).
• Insufficient cooling for the brake resistor (e.g., blocked airflow, fan failure, enclosure too small for heat dissipation).
• Incorrect temperature sensor connected to the brake resistor, or its feedback wiring is shorted/faulty.
• Drive parameter `P43.12` (Brake resistor temp limit) set too low for the application's normal operating conditions.

Click steps to track your progress.

1. 1

   Measure the actual temperature of the brake resistor (e.g., with an IR thermometer) during operation and compare it to the drive's displayed temperature (if available, e.g., `r43.01` (BR actual temperature)).

2. 2

   Verify the brake resistor's rated power (`P43.09` (Brake resistor power)) and nominal resistance (`P43.08` (Brake resistor resistance)) are correctly entered in the drive parameters.

3. 3

   Evaluate the application's braking requirements and compare them against the brake resistor's specifications to determine if it is adequately sized.

4. 4

   Inspect the brake resistor's mounting location for proper ventilation and clear any obstructions to airflow. Ensure any cooling fans are operating.

5. 5

   Adjust `P43.12` (Brake resistor temp limit) to a higher value if the current setting is unnecessarily low, *only after* confirming actual temperatures are within safe operating limits.